Mix one tablespoon oil, paprika, oregano, cumin, chilli powder, salt, onion powder and garlic powder together.
Cut the chicken breasts into halves vertically so you have 8 fillets. Mix the marinade into the chicken. Heat the other tablespoon oil in a pan and brown the chicken on either side, about a minute on each side. It's totally fine if not fully cooked as it will cook further in the sauce
In the same pan add the tomato paste, sugar and chicken broth. Simmer for about 2 minutes until it reduces just a little
Shred or chop the chicken breasts and add it to the sauce. Cook for a minute or until breasts are fully cooked. Do not over cook
Fill the taco shells with the chicken and top with the tomato, onion, jalapeno, avocado, coriander, lettuce and sour cream